CRA6 AN UNCOMMON COEXISTENCE: MUCOSA-ASSOCIATED LYMPHOMA TISSUE (MALT) LYMPHOMA AND PULMONARY TUBERCULOSIS

Wan Yi Leong, Umadevi A. Muthukumaru, Irfhan Hyder Ali
Penang General Hospital, Malaysia

Case presentation: 59-year-old male with several comorbidities. No previous history of tuberculosis infection. Multiple investigations performed due to persistent collapse of the right lower lobe with mediastinal lymphadenopathy for more than one year showed negative results. He was subsequently diagnosed as smear-negative pulmonary tuberculosis after his bronchoalveolar lavage detected MTB via the Xpert MTB/RIF test, in light of his clinical symptoms and radiological appearance remaining unchanged even after defaulting one year of treatment. Following the commencement of anti-tuberculosis treatment, follow-up radiographic imaging indicated a worsening consolidation in the right lower lobe. Repeated bronchoscopy revealed additional irregularities and abnormalities noted in the mucosa, leading to total obstruction of the right lower lobe bronchus. A low-grade B-cell neoplasm consistent with marginal zone lymphoma is present, and tissue cultures for MTB yielded negative results.

Discussion: Gene Expert can even yield false-positive results in tuberculosis-naïve patients. GeneXpert may generate false-positive results even in low Mycobacterium burden and potential contamination. TB infection is an independent risk factor for all malignancies, particularly in haematological malignancies, possibly due to chronic infection inducing an inflammatory state that undermines the normal immune system.

The question remains whether this is genuine TB infection provoking a chronic inflammatory state that compromises the natural immune system, promoting abnormal cell proliferation, or a false positive result due to contamination during bronchoscopy or non-viable TB organism.  It's also the possibility of the patient having active TB disease concurrently with a haematological malignancy.

Conclusion: It's essential to maintain surveillance if abnormalities persist or to reevaluate individuals upon onset of new symptoms, regardless of prior negative test results. The interpretation of Gene-Xpert MTB/RIF results must be conducted with caution, integrated with clinical symptoms as well as the use of imaging to minimise misdiagnoses.